Emit warnings for keywords selected to be reserved in the future

docs/assembly.rst

@@ -46,6 +46,7 @@ Solidity language without a compiler change.
     pragma solidity >=0.4.16 <0.9.0;
 
     library GetCode {
+        // This will report a warning - at you will be promoted to reserved keyword
         function at(address addr) public view returns (bytes memory code) {
             assembly {
                 // retrieve the size of the code, this needs assembly

libsolidity/analysis/SyntaxChecker.cpp

@@ -391,6 +391,9 @@ bool SyntaxChecker::visit(ContractDefinition const& _contract)
 				"Functions are not allowed to have the same name as the contract. "
 				"If you intend this to be a constructor, use \"constructor(...) { ... }\" to define it."
 			);
+
+	checkFutureKeyword(_contract);
+
 	return true;
 }
 
@@ -477,6 +480,8 @@ bool SyntaxChecker::visit(FunctionDefinition const& _function)
 	else if (!_function.isImplemented() && !_function.modifiers().empty())
 		m_errorReporter.syntaxError(2668_error, _function.location(), "Functions without implementation cannot have modifiers.");
 
+	checkFutureKeyword(_function);
+
 	return true;
 }
 
@@ -508,5 +513,31 @@ bool SyntaxChecker::visitNode(ASTNode const& _node)
 		solAssert(m_sourceUnit);
 		solAssert(m_sourceUnit->experimentalSolidity());
 	}
+	auto const* declaration = dynamic_cast<Declaration const*>(&_node);
+	if (declaration)
+		checkFutureKeyword(*declaration);
 	return ASTConstVisitor::visitNode(_node);
 }
+
+
+void SyntaxChecker::checkFutureKeyword(Declaration const& _declaration)
+{
+	std::set<ASTString> const futureKeywords = {
+		"transient",
+		"layout",
+		"at",
+		"error",
+		"super",
+		"this"
+	};
+		if (futureKeywords.count(_declaration.name()))
+		m_errorReporter.warning(
+			6335_error,
+			_declaration.location(),
+			fmt::format(
+				"\"{}\" will be promoted to reserved keyword in the next breaking version"
+				" and will not be allowed as an identifier anymore.",
+				_declaration.name()
+			)
+		);
+}

libsolidity/analysis/SyntaxChecker.h

@@ -66,6 +66,10 @@ class SyntaxChecker: private ASTConstVisitor
 	/// without a block.
 	void checkSingleStatementVariableDeclaration(ASTNode const& _statement);
 
+	/// Reports a warning if the declaration name is scheduled to be
+	/// promoted to a keyword in the near future.
+	void checkFutureKeyword(Declaration const& _declaration);
+
 	bool visit(IfStatement const& _ifStatement) override;
 	bool visit(WhileStatement const& _whileStatement) override;
 	void endVisit(WhileStatement const& _whileStatement) override;

libyul/AsmAnalysis.cpp

@@ -298,6 +298,7 @@ void AsmAnalyzer::operator()(VariableDeclaration const& _varDecl)
 	for (auto const& variable: _varDecl.variables)
 	{
 		expectValidIdentifier(variable.name, nativeLocationOf(variable));
+		checkFutureReservedKeyword(variable.name, nativeLocationOf(variable));
 	}
 
 	if (_varDecl.value)
@@ -326,6 +327,7 @@ void AsmAnalyzer::operator()(FunctionDefinition const& _funDef)
 {
 	yulAssert(!_funDef.name.empty());
 	expectValidIdentifier(_funDef.name, nativeLocationOf(_funDef));
+	checkFutureReservedKeyword(_funDef.name, nativeLocationOf(_funDef));
 	Block const* virtualBlock = m_info.virtualBlocks.at(&_funDef).get();
 	yulAssert(virtualBlock, "");
 	Scope& varScope = scope(virtualBlock);
@@ -953,3 +955,30 @@ void AsmAnalyzer::validateObjectStructure(langutil::SourceLocation const& _astRo
 		}
 	}
 }
+
+void AsmAnalyzer::checkFutureReservedKeyword(YulName _identifier, langutil::SourceLocation const& _location)
+{
+	std::set<std::string> futureReservedKeywords{"leave"};
+	if (m_evmVersion < langutil::EVMVersion::london())
+		futureReservedKeywords.insert("basefee");
+	if (m_evmVersion < langutil::EVMVersion::paris())
+		futureReservedKeywords.insert("prevrandao");
+	if (m_evmVersion < langutil::EVMVersion::cancun())
+	{
+		futureReservedKeywords.insert("blobbasefee");
+		futureReservedKeywords.insert("blobhash");
+		futureReservedKeywords.insert("mcopy");
+		futureReservedKeywords.insert("tstore");
+		futureReservedKeywords.insert("tload");
+	}
+	if (futureReservedKeywords.count(_identifier.str()))
+		m_errorReporter.warning(
+			5470_error,
+			_location,
+			fmt::format(
+				"\"{}\" will be promoted to reserved keyword in the next breaking version "
+				"and will not be allowed anymore as an identifier.",
+				_identifier.str()
+			)
+		);
+}

libyul/AsmAnalysis.h

@@ -128,6 +128,8 @@ class AsmAnalyzer
 
 	void validateObjectStructure(langutil::SourceLocation const& _astRootLocation);
 
+	void checkFutureReservedKeyword(YulName _identifier, langutil::SourceLocation const& _location);
+
 	yul::ExternalIdentifierAccess::Resolver m_resolver;
 	Scope* m_currentScope = nullptr;
 	/// Variables that are active at the current point in assembly (as opposed to

test/libsolidity/syntaxTests/constants/constant_state_variable_named_transient.sol

@@ -2,3 +2,4 @@ contract C {
     int constant public transient = 0;
 }
 // ----
+// Warning 6335: (17-50): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/dataLocations/data_location_in_function_type_fail.sol

@@ -7,5 +7,6 @@ library L {
 
 // ----
 // Warning 6162: (251-267): Naming function type parameters is deprecated.
+// Warning 6335: (251-267): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (159-173): Data location must be "memory" or "calldata" for parameter in function, but "storage" was given.
 // TypeError 6651: (251-267): Data location must be "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/externalFunction/function_argument_location_specifier_test_external_transient.sol

@@ -2,4 +2,5 @@ contract test {
     function f(bytes transient) external;
 }
 // ----
+// Warning 6335: (31-46): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (31-46): Data location must be "memory" or "calldata" for parameter in external function, but none was given.

test/libsolidity/syntaxTests/dataLocations/internalFunction/function_argument_location_specifier_test_internal_transient.sol

@@ -2,4 +2,5 @@ contract test {
     function f(bytes transient) internal {}
 }
 // ----
+// Warning 6335: (31-46): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (31-46): Data location must be "storage", "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/libraries/library_function_with_data_location_transient.sol

@@ -9,6 +9,14 @@ library L {
     function i2() external pure returns (uint[] transient) { }
 }
 // ----
+// Warning 6335: (28-44): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (103-119): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (141-157): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (218-234): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (256-272): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (329-345): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (367-383): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (444-460): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (28-44): Data location must be "storage", "memory" or "calldata" for parameter in function, but none was given.
 // TypeError 6651: (103-119): Data location must be "storage", "memory" or "calldata" for return parameter in function, but none was given.
 // TypeError 6651: (141-157): Data location must be "storage", "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/libraryExternalFunction/function_argument_location_specifier_test_external_transient.sol

@@ -2,4 +2,5 @@ library test {
     function f(bytes transient) external {}
 }
 // ----
+// Warning 6335: (30-45): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (30-45): Data location must be "storage", "memory" or "calldata" for parameter in external function, but none was given.

test/libsolidity/syntaxTests/dataLocations/libraryInternalFunction/function_argument_location_specifier_test_internal_transient.sol

@@ -2,4 +2,5 @@ library test {
     function f(bytes transient) internal pure {}
 }
 // ----
+// Warning 6335: (30-45): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (30-45): Data location must be "storage", "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/privateFunction/private_function_parameters_location_transient.sol

@@ -2,4 +2,5 @@ contract C {
     function f(uint[] transient) private pure {}
 }
 // ----
+// Warning 6335: (28-44): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (28-44): Data location must be "storage", "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/privateFunction/private_function_return_parameters_location_transient.sol

@@ -2,4 +2,5 @@ contract C {
     function f() private pure returns (uint[] transient) {}
 }
 // ----
+// Warning 6335: (52-68): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (52-68): Data location must be "storage", "memory" or "calldata" for return parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/publicFunction/function_argument_location_specifier_test_public_transient.sol

@@ -2,4 +2,5 @@ contract test {
     function f(bytes transient) public;
 }
 // ----
+// Warning 6335: (31-46): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (31-46): Data location must be "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/publicFunction/public_function_return_parameters_location_transient.sol

@@ -2,4 +2,5 @@ contract C {
     function h() public pure returns(uint[] transient) {}
 }
 // ----
+// Warning 6335: (50-66): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (50-66): Data location must be "memory" or "calldata" for return parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/transient_function_type_parameter.sol

@@ -3,3 +3,4 @@ contract C {
 }
 // ----
 // Warning 6162: (27-41): Naming function type parameters is deprecated.
+// Warning 6335: (27-41): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/duplicateFunctions/illegal_names_exception.sol

@@ -8,5 +8,7 @@ contract C {
 	}
 }
 // ----
+// Warning 6335: (61-88): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (90-118): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // Warning 2319: (61-88): This declaration shadows a builtin symbol.
 // Warning 2319: (90-118): This declaration shadows a builtin symbol.

test/libsolidity/syntaxTests/duplicateFunctions/illegal_names_functions.sol

@@ -10,6 +10,8 @@ contract C {
     }
 }
 // ----
+// Warning 6335: (84-117): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (123-155): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (17-78): The name "_" is reserved.
 // DeclarationError 3726: (84-117): The name "super" is reserved.
 // DeclarationError 3726: (123-155): The name "this" is reserved.

test/libsolidity/syntaxTests/enums/illegal_names.sol

@@ -21,6 +21,10 @@ contract C {
     E e;
 }
 // ----
+// Warning 6335: (0-19): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (20-40): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (72-76): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (82-87): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (0-19): The name "this" is reserved.
 // DeclarationError 3726: (20-40): The name "super" is reserved.
 // DeclarationError 3726: (41-57): The name "_" is reserved.

test/libsolidity/syntaxTests/events/illegal_names_exception.sol

@@ -5,5 +5,7 @@ contract C {
 	event _();
 }
 // ----
+// Warning 6335: (80-93): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (95-109): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // Warning 2319: (80-93): This declaration shadows a builtin symbol.
 // Warning 2319: (95-109): This declaration shadows a builtin symbol.

test/libsolidity/syntaxTests/events/illegal_names_exception_file_level.sol

@@ -2,3 +2,6 @@
 event this();
 event super();
 event _();
+// ----
+// Warning 6335: (66-79): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (80-94): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/freeFunctions/illegal_names.sol

@@ -10,6 +10,8 @@ contract C {
 	}
 }
 // ----
+// Warning 6335: (0-18): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (19-38): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (0-18): The name "this" is reserved.
 // DeclarationError 3726: (19-38): The name "super" is reserved.
 // DeclarationError 3726: (39-54): The name "_" is reserved.

test/libsolidity/syntaxTests/functionTypes/function_type_with_transient_param.sol

@@ -4,5 +4,7 @@ contract C {
 }
 // ----
 // Warning 6162: (27-41): Naming function type parameters is deprecated.
+// Warning 6335: (27-41): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // Warning 6162: (69-85): Naming function type parameters is deprecated.
+// Warning 6335: (69-85): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (69-85): Data location must be "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/immutable/illegal_names.sol

@@ -4,6 +4,8 @@ contract C {
     uint immutable this;
 }
 // ----
+// Warning 6335: (17-37): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (65-84): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (17-37): The name "super" is reserved.
 // DeclarationError 3726: (43-59): The name "_" is reserved.
 // DeclarationError 3726: (65-84): The name "this" is reserved.

test/libsolidity/syntaxTests/immutable/immutable_state_var_named_transient.sol

@@ -2,3 +2,4 @@ contract C {
     address public immutable transient;
 }
 // ----
+// Warning 6335: (17-51): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/inlineAssembly/blobhash_pre_cancun_not_reserved.sol

@@ -17,3 +17,5 @@ contract C {
 // ====
 // EVMVersion: <=shanghai
 // ----
+// Warning 5470: (98-106): "blobhash" will be promoted to reserved keyword in the next breaking version and will not be allowed anymore as an identifier.
+// Warning 5470: (237-303): "blobhash" will be promoted to reserved keyword in the next breaking version and will not be allowed anymore as an identifier.

test/libsolidity/syntaxTests/inlineAssembly/prevrandao_allowed_function_pre_paris.sol

@@ -18,3 +18,5 @@ contract C {
 // ====
 // EVMVersion: <paris
 // ----
+// Warning 5470: (101-111): "prevrandao" will be promoted to reserved keyword in the next breaking version and will not be allowed anymore as an identifier.
+// Warning 5470: (255-323): "prevrandao" will be promoted to reserved keyword in the next breaking version and will not be allowed anymore as an identifier.

test/libsolidity/syntaxTests/modifiers/transient_parameter.sol

@@ -2,4 +2,5 @@ contract A {
     modifier mod2(uint[] transient) { _; }
 }
 // ----
+// Warning 6335: (31-47): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (31-47): Data location must be "storage", "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/nameAndTypeResolution/shadowsBuiltin/illegal_names_function_parameters.sol

@@ -16,6 +16,10 @@ contract C {
     }
 }
 // ----
+// Warning 6335: (28-38): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (70-79): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (167-177): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (238-247): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (28-38): The name "super" is reserved.
 // DeclarationError 3726: (70-79): The name "this" is reserved.
 // DeclarationError 3726: (111-117): The name "_" is reserved.

test/libsolidity/syntaxTests/nameAndTypeResolution/shadowsBuiltin/illegal_names_library_using_for.sol

@@ -19,6 +19,8 @@ contract C {
     using _ for int;
 }
 // ----
+// Warning 6335: (0-49): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (51-99): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (0-49): The name "super" is reserved.
 // DeclarationError 3726: (51-99): The name "this" is reserved.
 // DeclarationError 3726: (100-145): The name "_" is reserved.

test/libsolidity/syntaxTests/nameAndTypeResolution/shadowsBuiltin/this_super.sol

@@ -5,6 +5,8 @@ contract C {
     }
 }
 // ----
+// Warning 6335: (52-62): "super" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (76-85): "this" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (52-62): The name "super" is reserved.
 // DeclarationError 3726: (76-85): The name "this" is reserved.
 // Warning 2319: (52-62): This declaration shadows a builtin symbol.

test/libsolidity/syntaxTests/parsing/contract_named_transient.sol

@@ -1 +1,3 @@
 contract transient {}
+// ----
+// Warning 6335: (0-21): "transient" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/storageLayoutSpecifier/contract_named_at.sol

@@ -1,2 +1,3 @@
 contract at layout at 0x1234ABC { }
 // ----
+// Warning 6335: (0-35): "at" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/storageLayoutSpecifier/contract_named_layout.sol

@@ -1,2 +1,3 @@
 contract layout layout at 0x1234ABC { }
 // ----
+// Warning 6335: (0-39): "layout" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/storageLayoutSpecifier/contract_with_members_named_layout_and_at.sol

@@ -3,3 +3,5 @@ contract C layout at 0x1234 {
     function at() public pure { }
 }
 // ----
+// Warning 6335: (34-45): "layout" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (51-80): "at" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/storageLayoutSpecifier/hex_string_cast.sol

@@ -1,3 +1,4 @@
 contract at layout at uint40(bytes5(hex"0011223344")) { }
 // ----
+// Warning 6335: (0-57): "at" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6396: (22-53): The base slot of the storage layout must evaluate to a rational number.

test/libsolidity/syntaxTests/storageLayoutSpecifier/literal_cast.sol

@@ -1,3 +1,4 @@
 contract at layout at uint(42) { }
 // ----
+// Warning 6335: (0-34): "at" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6396: (22-30): The base slot of the storage layout must evaluate to a rational number.

test/libsolidity/syntaxTests/storageLayoutSpecifier/type_uint_max.sol

@@ -1,3 +1,4 @@
 contract at layout at type(uint).max { }
 // ----
+// Warning 6335: (0-40): "at" will be promoted to reserved keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6396: (22-36): The base slot of the storage layout must evaluate to a rational number.